A theoretical model is developed to explain oil consumption in IC engines, based on the mechanism of oil being blown from a puddle directly below the top ring gap through the top ring gap into the combustion chamber during top ring reversal. This phenomenon is widely reported in the literature and is hereafter deemed the puddle theory of oil consumption. The model developed is supported by experiments conducted on a small, production single-cylinder diesel engine at various speeds using two oils. The collected data were used to construct semi-empirical, non-dimensional scaling laws to predict oil consumption. The formulas presented are capable of predicting oil consumption within ten percent, the experimental accuracy.Presented at the 48th Annual Meeting in Calgary, Alberta, Canada May 17–20, 1993